Conventionally, there are multi-air conditioners having a plurality of outdoor units (heat source units) and numerous indoor units (utilization units) in a single refrigerant circuit. For example, a multi-air conditioner is described in JP-A Publication No. 2001-41528 in which a plurality of compressors is designed to have a more uniform operating time while a plurality of outdoor units is designed to have a more uniform operating time. Also, a multi-air conditioner is described in JP-A Publication No. 11-63711 that is provided with a compressor, a plurality of outdoor units having an outdoor heat exchanger and an accumulator, a plurality of indoor units, a gas refrigerant communication pipe and a liquid refrigerant communication pipe that are shared in the two units, and a bypass circuit for feeding liquid refrigerant inside the accumulator of an outdoor unit to the outdoor heat exchanger of another outdoor unit.